Sealed containers are typically used in conjunction with food and other materials to be protected from moisture and the environment, or used with liquids and are to be isolated from spillage. Most sealed containers commercially available have compromised the sealing engagement in order to facilitate a snap shut closure. Quick engagement structures don't typically produce as strong of a seal as a more extended seal with significant sealing forces. Conversely, a good seal typically involves a complex locking arrangement or an extended seal. However, most complex locking arrangements or extended high pressure seals are inconsistent with ease of use and low expense.
The need for an efficient and easily operable seal is especially needed with respect to food containers which may be subjected to microwave use. The failure to form a lid hugging seal can cause containers holding the heated food to explode in the microwave causing damage and a mess. The instant container includes a superior seal as well as a pressure relief valve to that it can be employed to maximum effect in a microwave to insure that the lid stays on. If the pressure exceeds the pressure rating of the safety/pop valve assembly, which will typically be far less than the pressure necessary to dislodge the sealed lid, the safety/pop valve assembly will open to enable gaseous pressure to subside.
Sealing systems and container systems with secure seals can create significant problems for users. Where the seal is good, the use of the container may be accompanied by difficulty in sealing, requiring significant strength by the user. Where the seal is strong, removing the lid can cause the user to use two hands where the lid has significant holding force onto the container. This can cause spillage and mess on either opening or closing. Causing a user to press down hard can either trip a vapor relief valve, if present, or it can cause pressure discharged ejection of material between the lid and container before sealing occurs. On opening, any lifting beyond simple breaking of the seal by lifting the corner can result in a container which is so frictionally engaged with the lid that lifting of the lid simply lifts the lid and container while in partially opened condition, to then cause spillage.
One of the difficulties in sealing a container is knowing when it is sealed. Many commercially available containers have lids which are pressed onto containers, but don't indicate when sealing has occurred. This causes a user to over press and potentially squeeze out contents before sealing, or it causes the user to have to stop what they are doing and focus full attention on the evenness of the attached lid as an indication of sealing. Most commercially available sealing systems are so friction laden that there is little or no indication that full sealing has occurred without close inspection. Nearly everyone has experienced spillage from a container which was not closely inspected and visually tested before use or storage.
What is needed is a sealing system which provides ease of engagement on sealing accompanied by some quick and easy indication of sealing. An indication which indicates sealing and which does not require close inspection is needed. An indication which assures of good sealing other than visual and which triggers another of the users senses would be most helpful. What is also needed is a system which facilitates quick unsealing in a way in which the lid does not cling to the container so that it can only be removed by a peeling and gross force separation action. The needed system will facilitate reliability in sealing and unsealing which will reduce spillage and lack of sealing.